A study at the University of Central Lancashire found that over-emphasising prominent features on people's faces made them twice as easy to identify than before.Link
The researchers used computer software to alter the faces of 18 celebrities which had been created using three standard photofit techniques. The faces were then turned into caricatures by exaggerating certain features, such as the size of a person's ears, forehead or nose, by as much as 50%.
(Image credit: Dad, a Creative Commons Attribution licensed picture from PhylB's Flickr photostream)
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.